Throttle valve mechanism



July 1s, 1944.Y

THROTTLE VALVE MECHANISM v'Filed April 25, 1942 l '7 H lNvENToR A171mmH. MEYER.

Y BY

m/,mawMdJ j ATTORNEY F. A. yNn-:YE'R v 2,353,915 'V Patented July 18,1944 Westinghouse Electric & Manufacturing Company, East Pittsburgh,Pa.,"a,corporation of Pennsylvania Application April 23, 1942, SerialN0. 440,153

6 Claims.

The invention relates to .throttle valves of the general type shown anddescribed in the patent to Schwendner, No. 1,769,968, July 8, 1930, andit has for an object to provide apparatus of this character whereincontrol is easier because of the change in port area being maderelatively less for a given movement, whereby better control of the oilpressure is had and the possibility of accidental tripping by suddenmovements of the handwheel is diminished. l0

A further object of the invention is to provide apparatus of the abovecharacter which insures of an increased minimum oil pressure under thepiston so as to insure of tripping of the valve at partialloadsespecially when it is located below the turbine or prime mover inwhich case the static head of oil may be equivalent to or almostequivalent to the pressure necessary to sustain the valve.

A further object of the invention is to provide apparatus of the abovecharacter wherein tripping of the throttle valve in open position due tosurges in oil pressure is greatly minimized. Y

A further object of the invention is to provide a throttle valveoperating cylinder with control and tripping valve features, the controlvalve including a spring which serves to urge the tripping valve intosealing position.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawing, Vforming a partl of this application, inwhich:

Fig. l is a fragmentary side elevational ,view

of a turbine showing the control and throttle valve features in sectionand drawn to larger scale; and

Figs. 2 and 3 are sectional detail views'showing the servo-motorcontrolling valve.

In the drawing, the turbine or prime mover 9 is supplied with a steamsupply conduit I0 which has a throttle valve, at II, the latter beingoperated by means of the motor device, at I2.` An

impeller I3, or other suitable device, provides oil v46 under pressuresupplied through the. orifice I4 to the motor device, at I2. Thethrottle valve includes a seat I6 with which cooperates the movablevalve member II connected to the stem I8 by well-knownpressure-balancing means, at I9, 50

facilitating opening of the valve. The stem I8 is connected to themovable element of the motor device, at I2. A pressure relief valve 20fori the motor device is normally held closed but is opened I The motordevice, at I2, includes a housing 2l having an inner 'cylindrical bore22 containing the 'operating piston 23. Thev operating piston has a stemstructure 24 attached by suitable coupling means 25 to the stem I8.Thus, the throttle valve is opened and closed by upward and downwardmovement of the piston 23.

Within the housing, there is disposed a spring 26 acting on the piston23 to move the throttle valve in `a closing direction. The piston is'moved against the force of the spring 26 by means of oil pressureadmittedto the pressure space 28 at the side of the'piston opposite tothe spring space 29, oil under pressure being supplied to the pressurespace by meansof the orifice I4. It will be apparent, therefore, that;if the pressure in the space 28 is suddenly relieved, the rate of supplyof oil thereto being limited by the orice I4, the spring 26 will beeffective to move the piston and the throttle valvein a closingdirection.

The piston 23 is formed with a passage 3l) which connects the space 28withthe central opening 3I formed in the piston and whose discharge orupper end 32 is arranged to communicate with the spring space, thelatter being provided with an oil drain or overflow opening 33. Thedischarge end 32 of the central opening is provided by means of a flatplate 34 having a flat seat 35 with which the cup valvev 36y cooperates.As long'as the annular lip of the cup valve 36 is in sealing engagementlwith the at surface 35, then pressure of oil builds up underneath thepiston 23 `to move the latter upwardly or in a direction to open thethrottle valve. On the otherhand, if the cup valve 36 moves away fromthe seat, then the pressure of oil in the space 28 is suddenly releasedand the spring 25 closes the throttle valve.

The cup valve 36 has a sleeve portion 31 slidable on o r telescopicallyarranged with respect to the sleeve member 33.V TheA sleeve member has acentral bore 39 which telescopically receives the lower end yof the stem40. `A channel 4I vis formedin the sleeve member and extendslongitudinally thereof, the upper end of the channel being in continuouscommunication with the spring space 29 andy its lower end 42 beingarranged to be lapped by the slide valveelement 43 of the sleeve portion31. A spring 44 encompasses the sleeve portion 31 and the sleeve member38, the-upper end of the spring abutting the collar 45 and the lower endengaging the upper surface 45 of the cup valve 36 so as to exert forceon the cup valve tending to move the latter into by the emergency oroverspeed trip device, at 20a. A|55 sealing engagementl with the seatingsurface 35.

the threaded portion 50, the stem has a portion.

52 engageable with a handwheel 53 so that the stem may be turned. K

Assuming that the slide valve element 43 of the sleeve portion 31 lapsthe lower end42 of the channel 4|, then upward movement of the stem isfollowed by upward movement of the piston due to the pressure of oilacting therebelow. With the piston sustained by oil pressure, if thestem 40 is moved downwardly, then the sleeve` portion 38 moves with itto place the channel 4| in communication with the pressure space,wherelby oil will be by-passed from the pressure space and the springwill be effective to move the piston downwardly, such downward movementof the piston tending, because of the spring 44, to bring about thelapping condition of the slide valve portion 43 with respect to thelower end 42 of the channel. Thus, it will be seen that upward anddownward movements of the stem 40 are accompanied by following movementsof the piston 23, the piston being moved by the spring 26 in a closingdirection, when pressure in the pressure space is relieved, and beingmoved in an opening direction upon upward movement on account ofpressure building up in the pressure space due to restriction of escapethrough the channel 4| The housing 2| carries an adjustable sleeve 55whose lower end cooperates with the seat 35 to limit upward or openingmovement of the piston. The sleeve 55 is so adjusted that the lower endthereof is spaced from the seat 35, when the throttle valve is in closedposition, such that, in relation to the spacing'of the stop collar 56 onthe stem 40 from the nut 5|, with opening movement of the piston limitedby the sleeve, continued upward movement of the screw 50 until itscollar 56 engages the lower end of the nut 5| assures that, due to thespring 44, the sleeve valve portion 43 shall lap the lower end of thepassage 42 by a slight amount, for example le of an inch (see Fig. 3). n

With the seat l35 spaced from the sleeveV 55 as just stated, it will beapparent that, with downward movement of the throttle valve element I8then, with the cup valve 36 engaging the seat 35 the stem may be moveddown further to move the sleeve member 38 downwardly relatively to thesleeve portion 31 to open the lower end of the channel 4|. As shown, thesleeve member 38 has an abutment 58 which is normally spaced a slightdistance from the piston surface 59, for example, M3 of an inch. Thus,it is assured that with the piston 23 in its lowermost position and theabutment 58 engaging the piston surface 59, the lower` end of thechannel 4| will be opened Re of an inch (see Fig. 2). In this'way, solong as the throttle valve is held in closed position by means of thestem, it is impossible, because of relief affordedj by the by-passingopen channel 4|, for pressure to build up underneath the piston.

With the piston 23 in the throttle closing position, as shown, and withthe stem 40 holding the abutment 58 in contact with the surface 59,

engaging thel seat |1.

piston 23 limited by the the first effect of upward movement of the stemis to cause the sleeve member 38 to follow it, the force of the spring44 being effective for this purpose; and, just as soon as the valveportion 43 laps the lower edge 42 of the channel, then pressure of oilacting below the piston causes the latter Vto move upwardly.. Upwardmovement of thewpiston 'will continue so long as the screw is movedupwardly. If the screw is moved upwardvly only for a fraction of itsstroke, then the position of the piston is determined by opposing forcesof the spring 26 and of pressure of oil in the pressure space 28, upwardmovement of the piston opening the port area of communication of thechannel 4| with the pressure space to bring about equlilibrium of fluidpressure and spring forces. i

In the event of sudden drop of pressure 1n the 4pressure spa-ce 28, due,for example, to operation of the overspeed trip device, the piston 23 ismoved downwardly by the spring 26, and, as soon as its seat 35 leavesthe cup valve 36, copious discharge area for oil is thereby providedwith the result that the throttle valve is quickly closed by the spring.

While the invention has been shown` in but one form, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various changes and modifications without departing fromthe spirit thereof, and it is desired, therefore, that only suchlimitations shall vbe placed thereupon as are specifically set forth inthe appended claims.

What is claimed is:

1. Means for actuatingva throttle valve for a prime mover in response toan operating characteristic of the latter and comprising a cylinder, apiston in the cylinder, said piston dividing'the interior of thecylinder into a drainage space and a pressure space, av first springexerting force on the piston, means including an orifice for Supply ingliquid from a suitable source to the pressure space to exert force onthe piston in opposition to that of said spring, means for effectingsud# den release of lpressure in said pressure space; a threaded stemhaving its inner end disposed adjacent to the piston, means including anut for supporting the stem from the cylinder, said 'pis'J ton having anopening extending therethrough and providing for discharge of liquidfrom the pressure space to the drainage space, a valve in coveringrelation with respect to the discharge end of the opening andcooperating with the piston to interrupt ow through the latter, aniember abutting theinner end of the stem, a second yspring between saidmember and the valve, a by# pass passage formed in the abutmentv memberVand continuously open to the drainage space of the cylinder, a valveportion carried by said valve and slidable with respect to the membertooverlap. the inner end of the passage to interrupt vcommunicationthereof with the pressure chamber and to uncover the inner end of thepassage vto provide for communication thereof with the pressure chamber,said slide valve portion cooperating with the inner end of the passageto provide an area of communication thereof with the pressure spacewhich gradually increases or decreases with relative opening and closingmovements of the slide valve portion and of the abutment member from andtoward lapping position, and means for turning the stem.

2. Means for actuating a throttle valveY for a -prime mover in responseto an operating char;

acteristic of the latter and comprising a cylinder; a piston in thecylinder; said piston dividing the interior of the cylinder into adrainage space and a pressure space; a iirstY spring exerting force onthe piston; means including an orifice for supplying liquid from asuitable source to the pressure space to exert force on the piston inopposition to that of said spring; means for effecting sudden release ofpressure in said pressure space; a threaded stem having its inner enddisposed adjacent to the piston; means including a nut for supportingthe stem from the cylinder; said piston having an opening extendingtherethrough and providing for discharge of liquid from the pressurespace to the drainage space; Va valve in covering relation with respectto the discharge end of the openingr and cooperating with the piston tointerrupt flow through the latter; a member abutting the inner end ofthe stem; a second'spring between said member and the valve; a by-passchannel formed in the abutment member and continuously open to thedrainage space of the cylinder; a Valve portion carried by said valveand slidable with respect to the member to overlap the inner end of thechannel to interrupt communication thereof with the pressure chamber andto uncover the inner end of the passage to provide for communicationthereof with the pressure chamber; said slide valve portion cooperatingwith the inner end of the passage to provide an area of communicationthereof with the pressure space which gradually increases or decreaseswith opening and closing of the slide valve and of the abutment memberfrom and toward lapping position; a stop carried by the cylinder andadapted to contact with the piston to limit outward movement thereof; astop carried by the screw for limiting its outward movement; meansproviding for location of the stop carried by the cylinder such that,With the outward position of the piston limited thereby and with outwardmovement of the screw limited by its stop, said slide valve portion willlap the inner end of the bypass passage; means for limiting continuedinward movement of the screw after stopping of the piston due to seatingthe throttle valve in closed position so that the slide valve portionuncovers the inner end of the passage to place the latter incommunication with the pressure space; and means for turning the stem.

3. Means for actuating a throttle valve for a prime mover in response toan operating characteristic of the latter and comprising a cylinder; apiston in the cylinder; said piston dividing the interior of thecylinder into a drainage space and a pressure space; a first springexerting force on the piston; means including an orifice for supplyingliquid from a suitable source to the pressure space to exert force onthe piston in opposition to that of said spring; means for a effectingsudden release of pressure in said pressure space; a threaded stemhaving its inner end disposed adjacent to the piston; means including anut for supporting the stem from the cylinder; said piston having anopening extending therethrough and providing for discharge of liquidfrom the pressure space to the drainage space; a sleeve membertelescoping the inner end portion of the stem and closed at its innerend to abut the inner end of the stem; a valve member carried by thesleeve member and slidable longitudinally of the latter; said sleevemember having a passage continuously open t said drain space;l saidvalve member including Aacup valve portion and a slide valve portion;the cup valve portion cooperating with the piston to interrupt flowvthrough `the opening of the latter from thepressure space to the drainspace and the slide valve portion cooperating with the sleeve member tolap the inner end of said passage to interrupt communication of thelatter with the pressure space or to provide a variable area ofcommunication therewith dependent upon relative movement of the sleeveand valve members; a second spring carried by the sleeve member andacting on the'valve member to urge the latter to move toward saidpiston; and means for turning the stern. f l

4. Means for actuating a throttle valve for a prime mover in response toan operating'V characteristic of the latter and comprising a cylinder; apiston in the cylinder; said piston dividing the interior of thecylinder into a drainage space and a pressure space; a rst springexerting force on the piston; meansnincluding an orice for supplyingliquid from a suitable source tothe pressure space to exert force on thepiston in opposition to that of said spring; means for effecting suddenrelease of pressure in said pressure space; a threaded stem having itsinner end disposed adjacent to the piston; means including a nut forsupporting the stem from the cylinder; said piston having an openingextending therethrough and providing for discharge of liquid from thepressure space to the drainage space; a sleeve member telescoping theinner end portion of the stem and closed at its inner end to abut theinner end of the stem; a valve member carried bythe sleeve member andmovable longitudinally of the latter; said sleeve member having apassage continuously open to said drain space; said valve memberincluding a cup valve portion and a slide valve portion; the cup valveportion cooperating with the piston to interrupt flow through theopening of the latter from'the pressure space to the drain space andtheslide valve portion cooperating with the sleeve member to lap the innerend of said passage to interrupt communication of the latter with thepressure space or to provide a variable area of communication therewithdependent upon relative movement of the sleeve and valve members; asecond spring carried by the sleeve member and acting on the valvemember to urge the latter to move toward said piston; a stop carried bythe cylinder and adapted to contact with the piston to limit outwardmovement thereof; a stop carried by the screw for limiting outwardmovement thereof; means providing for location of the stop carried bythe cylinder such that, with the outward position of the piston limitedthereby and with outward movement of the screw limited by its stop, theslide valve portion will lap the inner end of the passage; means forlimiting continued inward movement of the screw after stopping of thepiston so that the slide valve portion uncovers the inner end of thepassage to place the latter in communication with the pressure space;and means for turning the stem.

5. Means for actuating a throttle valve for a prime mover in response toan operating characteristic of the latter and comprising a cylinder; apiston in the cylinder; said piston dividing the interior of thecylinder into a drainage space and a pressure space; a iirst springexerting force on the piston; means including an orifice for supplyingliquid from a suitable source to the pressure space to exert force onthe piston in opposition to that of said spring; means for effectingsudden release of pressure in said pressure space; a threaded stemhaving its inner end disposed adjacent to the piston; means including anut for supporting the stem from the cylinder; said piston having anopening extending therethrough and providing for discharge of liquidfrom the pressure space to the drainage space; a sleeve membertelescoping the inner end portion of the s-tem and having its inner endclosed to abut the inner end of the stem; a valve member carried by thesleeve member and movable longitudinally of the latter; said sleevemember havving a channel open to its outer surface and extendinglongitudinally thereof; said valve member including a cup valve portionand a sleeve valve portion; said cup valve portion cooperating with thepiston to ,interrupt flow through the opening of the latter from thepressure space to the drain space and said sleeve valve portion beingslidably mounted on the sleeve member and cooperating with the latter tolap the inner end of said channel to interrupt communication thereofwith the pressure space or to provide a variable area of communicationthereof with the latter dependent upon relative movement of the sleeveand valve members; a second spring carried by the sleeve member andacting on the valve member to urge the latter to move toward saidpiston; means carried by the sleeve member to retain the valve memberthereon when the cup valve portion is separated from the piston; andmeans for turning the stem.

6. Means for actuating a throttle valve for a prime mover in response toan operating characteristic of the latter and comprising a cylinder; apiston in the cylinder; said piston dividing the interior of thecylinder into a drainage space and a pressure space; a first springexerting force on the piston; means including an orifice for supplyingliquid from a suitable source to the pressure space to exert force onthe piston in opposition to that of said spring; means for effectingsudden release of pressure in said pressure space; a threaded stemhaving its inner end disposed adjacent to the piston; means including anut for supporting the stem from the cylinder; said piston having anopening extending therethrough and providing for discharge of liquidfrom the pressure space to the drainage space; a sleeve membertelescoping the inner end portion of the stem and closed at its innerend to abut the inner end of the stem; said sleeve member having spacedinner and outer collars; a valve member carried by the sleeve member andmovable longitudinally between the collars of the latter; said sleevemember having a channel open to the exterior thereof and continuouslyopen to said drain space; said inner collar being spaced inwardly fromthe inner end of the channel; said valve member including a cup valveportion and a sleeve valve portion slidable on the sleeve member; thecup valve portion cooperating with the piston to interrupt ilow throughthe opening of the latter from the pressure space to the drain space andsaid sleeve valve portion cooperating with the sleeve member to lap theinner end of said channel to interrupt communication of the latter witha pressure space or to provide a variable area of communication with thelatter dependent upon relative movement of the sleeve and valve members;a second spring between the outer collar and the valve member forexerting force on the latter; a stop carried by the cylinder and adaptedto contact with the piston to limit opening movement thereof; a stopcarried by the stem for limiting outward movement; thereof; meansproviding for location of the stop of the cylinder Such that, with theoutward position of the piston limited thereby and with outward movementof the screw limited by its stop, the sleeve valve portion will lap theinner end of the channel; means for limiting continued inward movementof the screw after stopping of the piston so that the sleeve valveportion uncovers the inner end of the channel to place the latter incommunication with the pressure space; and means for turning the stem.

FRANK A. MEYER.

